They all have tradeoff, but at least with Unisob there are no trusted federation required, unlike typical sidechain models that rely on a federated group of functionaries, this uses a single "bridge operator" that does not need to be fully trusted in the long run. Even if the bridge operator disappears or acts maliciously, users can withdraw their funds through a "sad path" withdrawal by providing proof of their withdrawal request and slashing the operator's posted collateral.

The bridge operator can use user deposits directly as collateral (Model A) or put up separate collateral (Model B) to back withdrawals, allowing more capital efficiency. Each user gets their own customized "withdrawal contract" that allows them to withdraw funds independently without relying on other users.

For certain use cases that prioritize permissionlessness and simplicity over shared security pools, this rethinking of sidechains could be suitable.